Filtering apparatus



March 8, 1927. 1,620,431

B. BRAMWELL FILTERING APPARATUS y y Filed June 14, 1926 4 Sheets-Sheet l 'March 8,\ 1927.

B. BRAMWELL FILTERING APPARATUS Filed June 14, 1926 4 Sheets-Sheet 5 March 8, 1927. 1,620,431

B. BRAMWEYLL FILTERING APPARATUS Filed June 14, A19,26 v 4 Sheets-Sheet 4 Patented Mar. 8, 1927.

BALFOUR BRAMWELL, 0F BELFAST, IRELAND.

FILTERING APPARATUS.

Application filed .Tune 14, 41926, Serial No. 115,300, and in Great Britain February 11, 1925.

deposition after washing upon the surface thereof.

One of the objects of the, invention is to .l eliminate the formation of any stationary sand in the filter bed and to ensure that the whole of the bed is disturbed and efficiently washed by the cleansing process, and this without any necessity to revolve the filter chamber or use a reverse flow through the filter bed. 1

Another object of the invention is to ensure the most effective use of the ffiltering material and prevent loss of the medium with the stream of filtrate, with which object the said stream or streams are caused to leave the filtering medium while travelling in an upward direction.

Another object of the invention is the elimination of perforated plates for supporting the filtering medium or of pipes and nozzles within the filtering chamber for collecting the filtrate and distributing the wash e water. y

According to the present invention an arrangement is provided whereby the liquid to be filtered flows in substantially vertical stream lines downwards through the effective part of the filter bed and the filtrate leaves the filter bed in an upward direction, the filtering material being self-supported in the filterchamber in such a manner that the whole ofA the filtering material may be withdrawn from the lowest point of the filter chamber for cleansing, the cleansed filtering material being subsequently returned to the filtering system. Y

To provide for collecting the filtrate at the bottom of the filter bed, instead of having the usual platform with nozzles or perforated plates and gauze or perforated pipes, an annular. collecting chamber is formed around the body portion of the filter chamber by means of a depending liner which is closed against the filter wall at the topfand is open at the bottom. The water in leaving the effective depth of the filter bed, which may conveniently be from the upper surface down tothe beginning of the tapering part of the filter chamber, turns upwards into e the annularchamber, the mouth of which is sufficiently wide to ensure that theveloeity of the filtrate streannd at this point will be comparatively smaii. Since, therefore, the filtrate leaves the sand in an upward direction and at a comparatively low speed, no filtering medium can possibly tbe Vcarried away with the effluent filtrate.

The withdrawal of the Sand from the bottom of the chamber and its transference to .a washing apparatus may be effected o'r prom'oted by means of a jet of water, injector fashion, in the known manner, the washing chamber being conveniently situated upon or near the top of the filter, so that the washed sand can be deposited'directly upon the surface of the filter bed.

Instead of returning the sand,` when Washed, to the same chamber, there may be provided an additional chamber, which may or may not be one of the filter chambers, in

'which the washed sand is separated from the washing water and from which it may be returned erher to the filter chamber from which it was withdrawn inthe first'instance, or to another filter chamber; or the additional chamber when filled with washed sand may itself be brought into use as a filter chamber. It is thus possible to have many filtering units with one common washing and sand and water separating chamber.

The invention will be mo-re particularly described with f reference tothe accompany- 1 ter. A depending magazine C is attached to ythe upper 4part of the filter chamber and is open at the bottom in order to form an annular chamber between the wall of the filter chamber and said magazine for the passage and discharge of the filtrate-in an upward direction. is the sand-washing chamber which is situated above the filter chamber and is inl/communication therewith. J, J J 2, J 3, J t are valves controlling the entrance and discharge pipes of the filter system. In ope-ration and when filtering the Water, the valves J, J are open and all the others are closed. lfVater enters the pipe E and is dis- -the annular chamber formed thereby and is discharged through the pipe G.

When it is required to cleanse the sand, valve J is closed and Valves J2, J3, J4 are opened. Clean water is injected under sufficient pressure through the pipe F into the sand in the pipe leading from the apex o1 the cone B and the kinetic energy of this water stirs u the sand and washes it up through the pipe I-I into the washer or separatorD, where the sand and water are separated, the cleansed sand being returned to the filter chamber, while the dirty water is led away through the pipe I either to waste or to a settling tank, where the impurities settle down and are drawn off as sludge and the settled water used again for washing purposes. During the cleansing operation the valve J is kept partially open, in order 0 maintain the pressure in the filter cham- In order to ensure more or less vertical stream lines down through the filter bed, the latter may be fitted with depending baffles. Such a construction is illustrated in Fig. 2, wherein the filter bed is divided into vertical sections by means of baffies K. The operation of tlns apparatus is similar to that shown in Fig. 1, the washedand separated sand being returned to the filter chamber through branch pipe M and a baffle L being provided, if required, in order to divert the incoming water to the outer filter beds.

Since the filtrate leaves the sand in an upward direction and at a comparatively low speed, no sand is carried away with the effluent filtrate. Should, however, the outlet openings be low, as for example in Fig. 2, the risk of some of the sand escaping into the filtrate is obviated by providing perforated plates or ganzes N over the outlet openings or at any other suitable point between the sand and the outlet openings. lVhen such perforated plates or ganzes are used they donot bear the weight of any of the sand, but act merely as a means for preventing the sand from being carried away with the efiuent filtrate.

In Fig. 3, in addition tothe annular chamber leading 4to the outlet for the filtrate, a central pipe O is provided which opens at the bottom into the filtering bed either at the same` level or at a different. level from the mouth of the annular chamber, and passes vertically upwards through the top of the filter' chamber A, if the latter is closed, and thence leads to the discharge pipe G for the ltrate. More than one of these pipes O may be providedl if r uired. i

In Fig. '4, instead of orming the filter chamber with a single conical or pyramidal bottom, each chamber A is formed with two such cones `or pyramids B, although more than two maybe provided if required. Each one is provided with a sand ejector F and l the sand from the several outlets is preferably discharged into a single sand washer and separator from which it is distributed over the upper surface of the filter bed by means of a plurality of discharge pipes M leading from the washing chamber D.

Figs. 5 and 6 illustrate in elevation and plan respectively, a filter unit wherein the sand washing and separating chamber 1s formed as a portion of the filter chamber by means of a perforated plate P which separates the top of the vfilter 'chamber into a sand washer and separator. The sand `and washing water fiow through the pipe H into said compartment through a branchpipe Q, opening into the side thereof, thereby giving the sand and water a circular motion.

' While the entire filter bed can be washed by a continuous or intermittent withdrawal from the lowest point and conveyance to a washing and separating chamber independently of any reverse iow of water through pipes', or nozzles or perforated plates at the bottom of the filter bed, it Vmay sometimes be convenient to provide for the removal of accumulated impurities from the upper surface ofthe filter bed. This ma be done by a reverse flow down the annu ar chamber, for example by opening the valve J and up through the filter bed, while at the same time the surface of the latter is broken up by revolving rakes, thedirty water passing out through an outlet from the water space near the top of the filtering chamber.

' Figs. 7-13 illustrate another embodiment of the present invention wherein, instead of returning the washed sand to the same chamber, it is preferred to provide one or more additionalchambers which form a filtering unit in which each chamber may be used as a filter chamber and a sand and dirty water separator. v

Figs. 7 and 8, which are diagrammatic drawings Iin elevation `and plan respectively, illustrate an arrangement wherein two filter chambers are employed which operate in the saine manner as described with reference to the other figures, but instead of returning the sand to they same chamber, for example chamber No. 1, it is ejected into chamber No. 2, which is empty, and when all the sand lhas been washed and discharged into this latter chamber this then becomes the filter chamber. The same process is repeated when it is required to discharge the sand from No. 2 chamber to N o. 1.

In Fig.y 9 an arrangement is illustrated in which three chambers are employed in association with each other. When working with three chambers, if for-example No. 3 chamber is empty at a given time and Nos.

1 and 2 chambers require cleansing, the filtering material is transferred in the manner de` scribed from No. 2 to No. 3 chamber and cleansed in the process, leaving No. 2 chamber empty to receive the filtering material from No. l chamber when that in turn re# available to receive the sand from No.` 3 chamber.

In either of the alternatives illustrated in Figs. 7-9 the pipe through which the sand is forced from the full chamber to the empty onevforms the sand washer. falls into the chamber the dirty water over- Hows to waste and a slight upward current of clean Water is passed through the chamber Whilst the same is settling in it Vin order to washout all the impurities and leave the sand clean in the chamber. therefore, in turn becomes a filter chamber and a sand and dirty water separator.

Fig. 10 illustrates the operation offan apparatus using two chambers. When filtering with No. 1 chamber in action valves R 7 and R9 are open. As in the other cases', v water enters through the pipe E above the sand, filters down through the filter bed, is turned upwards into the annular space and is discharged through the pipe G. In order t-o cleanse the sand in No. 1 chamber, valves R', R2 and R10 are shut and R3., R4 are opened, and valve R5 is partly opened, ac-

` cording to the pressure required. Valves R7, R8 on No. 2 chamber are closed and valve Rq is kept slightly open to give a reverse flow upwards through No. 2 chamber. The

' i kineticy energy of the water at F starts the sand in motion and washes it up through the pipe H to the top of No. 2 chamber. The sand falls tothe bottom of this chamber, gradually filling it, and the water which has been used to. wash and transfer the sand .from No. 1 chamber is run to waste through pipe I. When the sand has thus been washed and transferred from No. 1 to N o. 2 chamber, the latter then becomes the filter chamber and continues in operation as such until such time as the bed 'has become foul and requires cleansing, When the sand is transferred in the manner described to No. 1 chamber and cleansed in the process of transference.

If desired, instead of usin two or more similar chambersl for use as lter chambers and sand separators, an additional chamber As the sand Each chamber,

a separator to receive the ejected sand and Water and its contents would then be returned to Whichever filter chamber it has beenejected from'. Such an arrangement is illustrated in Fig. 11, where S 'is the sand and Water separator. As an example, when all the sand has been ejected from No. 1 filter chamber into the chamber S, during which thelatter is kept at a lower pressure than the filter chamber, it being either closed or open to the atmosphere, the sand would then be returned to No. 1 chamber, during which process the .pressure in the chamber S is kepthigher than the filter chamber, and subsevquent filter chambers may be treated likequires` cleansing. No. 1 chamber lis then` each large filter chamber is shown circular',`

but it can be rectangular or any other convenent shape.

Fig. 12 illustrates an arrangement wherein two filter units are employed and the main body portion A of each chamber is-divided into eight sections and has eight conical or pyramidal bottoms B B8, or any other number of sections and bottoms may be provided. S is the washer or sand and water separator, which may be closed or open to the atmosphere. The section marked B1 in filter chamber No. 2 in Fig. 12 is shown empty, the sand having been ejected into separator S, whence it 4'is returned to B1f To wash the Whole of the filter unit, each section lis treated in the same manner. T, T2 are the inlet pipes to each lter unit for the Water to be filtered, each pipe communieating independently With the upper portion of its particular filter chamber. V', V2 are the outlet pipes for the filtrate and which communicate with the annular spaces formed around the filter chambers.

This 4arrangement `of ejecting and discharging the sandand water into a separate empty chamber enables simpler apparat'us to be used for the ejection of the sand from the full chamber to the empty one and, moreover, enables the whole process Ato be operated under considerably lower pressure forv the eject-ion of the sand from the full chamber to the empty one, the washing or sand separating chamber being open to the atmosl phere and therefore at atmospheric pressure; or closed under any" suitable lower pressure than the chamber from which the sand is being ejected.

Having thus described the nature of-the taining wall.

of carrying the same into practical effect,'I claim:-

1. In filtering apparatus of the character described, a body of filtering material', an impervious magazine affording lateral sup-- port for a substantially vertical columnl of said filtering material and extending downwardly to a point determining the effective filtering depth for liquid introduced into the upper end of said column, said filtering material being laterally exposed in a zone below said magazine, means supporting said column below said zone and permitting discharge of filtering material, and a retaining wall outside said magazine intersecting the plane of the lower end of the latter and forming with the exterior of' said magazine a passagewayfor the upward flow of the filtrate from said zone of filtering material.

2. In filtering apparatus ofthe character' described, a plurality of the Vunits as claimed in claim l, interconnected, and valved means permitting the alternative use of .said units. 3'. In filtering apparatus of the character described, a plurality of the units as claimed in claim l, and a washing and separating chamber for the filtering material 'common to said units and to which said units are connected.

4.V A filtering apparatus according to claim l wherein the means for supporting the column of filtering material in the zone below the magazine consists of an inverted cone connected to the lower end of the rc- 5? Filtering apparatus comprising in combination a vetrical filter chamberr provided with an inverted conical-shaped bottom pontion, an inlet at the top of the filter chamber for the liquid to be filtered, an outlet at the bottom of said conical portion for the passage of the filtering material, an annular collecting chamber surrounding the body of the filter chamber, said collecting chamber being closed at the top and open at the bottom, a sand and Water separator communieating with the filter chamber, a conduit external to the filter chamber and leading from the outlet at the bottom of said conical portion to said sand and water separator, conduits communicatingwith. the filter chamber for the entrance of the liquid to be filtered and for the discharge of the filtrate and dirty Wash water respectively, valves con-V trolling all of the said conduits, and an injector nozzle opening into said first-mentioned conduit.

6. Filtering apparatus comprising a vertical chamber having an inverted conical Shaped bottom portion, an annular member vdepending from the upper end of said chamber and terminating short of the lower end of the latter and dividing said chamber'into an inner chamber .to contain filtering material and. au Outer Chamber into which the injector connected to said filtering material- Y ,receiving and washing means adjacent the connection of the latter to said conical shaped bottom portionot said vertical chamber for assisting in, the Withdrawal of the filtering material frbm said chamber and its delivery to said receiving and washing means.

. T. Filtering apparatus comprising in combination a plurality of chambersteach chamber being divided into vertical sections, each section having an inverted conical-shaped bottom portion, an annular collecting chamber surrounding the body portion of each section, said collecting chambers being closed at the top and open at the bottom, a'sand and Water separator, conduits communicating at one end with the top of the said separator and at the other e-nd with the bottom of the conical-shaped portions of the lter chamber, conduits communicating at one end with the bottom of the said separator and at y the other end with the top of the filter chambers, conduits communicating with the top ofthe lter chambers for the entrance of the liquid to be filtered, valves for controlling all of said conduits, and injector nozzles opening at the bottom of the conical-shaped bottom portions of the filter chambers into the first-mentioned conduits.

i 8. Filtering apparatus comprising a plurality of chambers, each chamber being divided into' vertical sections forming an inner chamber' to contain filtering material and an outer collecting chamber into which the filtered liquid may rise after its passage through said filtering material, each of said outer sections having an inverted coneshaped bottom portiondepending below the lower end of its associated inner section, valved conduits connected to the upper portions of said inner sections for the delivery thereto of liquid to be filtered, valved conduits connected to .the upper portions of said outer sections for the escape ot filteredliquid therefrom, a sand and liquid separator, valve-controlled conduitsk connecting the conical shaped bottom portions of said outer sections with the upper portion of said separator, and valve-controlled conduits each connecting the lower portion of said separator with one ofsaid inner sections.

9. Filtering apparatus. comprising in combination a plurality of filter chambers, means for ejecting the liltering material from one of said chambers and discharging it into another of said chambers and means for maintainingvsaid last-mentioned chamber at a lower` pressure than the first-mentioned chamber.-

10. Filtering apparatus comprising in combination a lilter chamber, a sand and water separator, means for ejecting the filtering material from said filter chamber and discharging it into said sand and water separator and means for maintaining the said separator at a lower pressure than the said filter chamber.

11. Filtering apparatus comprising a plu- .rality-of lter chambers, a sand and water separator mea-ns for ejecting the ltering material in each filter chamber .in turn and *dischargingit into the sand and Water sepa.- rator and means for maintaining the said separator lower pressure than the said filter cham ers.

In testimony whereof I have signed my' name to this specification,

\ BALFOUR BRAMWELL. 

